Flooding is not a new phenomenon in the south Dublin suburb of Rathfarnham.
There have been many occasions when the area’s rivers, tributaries and streams flowing down from the Dublin mountains have burst their banks and caused floods during periods of sustained rain.
In 1680, the aptly named Dr Gerard Boate, author of Ireland’s Natural History, observed that “the bridge at Rathfarnham was so high that a man on horseback could ride under it, and the water was so shallow that a child could wade through it, yet the river rose so rapidly that it often flowed over the bridge”.
In possibly the biggest flood ever recorded in Dublin, in 1802, bridges along the Liffey, Dodder and Poddle were swept away.
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A contemporary account said of the Poddle in Rathfarnham that it “overflowed to a greater height than was ever remembered, causing great distress to many poor people, who were banished from their habitations, particularly to those whose misfortune it is to reside in cellars”.
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In this century there have been floods in the south Dublin suburb that have caused water damage to houses in estates in the catchment of the rivers.
In response, South Dublin County Council (SDCC) has with the Office of Public Works (OPW), commenced a number of ambitious multimillion-euro flood alleviation schemes on the river Poddle, Whitechurch Stream and Owendoher, a tributary of the Dodder, along with the Dodder itself, that has long been prone to flooding.
The epicentre of the serious flooding incident in Rathfarnham this week was the Whitechurch Stream. It rises between Tibradden and Kilmashogue Mountains and flows 7.7km through Marlay Park and St Enda’s Park, before continuing beside the Whitechurch Road until it meets the Owendoher at Willbrook, close to a prominent Fanagan’s Funeral Home. The combined rivers then flow downhill into the Dodder.
A modest body of water, Whitechurch Stream was nonetheless identified as liable to flooding in a one in 100-year flood event.
The reasons are clear: it had low banks, had lost some of its existing defences and had no large uninhabited flood plains. The river flows underground in places into culverts, some of which were not big enough to contain increased volumes, especially when the stream becomes a torrent. The most recent flooding events, before this week, occurred in 2007 and 2011.
In late 2020, An Bord Pleanála gave permission to South Dublin County Council for the local authority and the OPW to proceed with flood defence along the Whitechurch Stream comprising a number of interventions, though the main protection would be the construction of robust and high flood defence walls.
Five years later, and only months short of its completion as a flood defence, the event it was meant to prevent happened.
What caused such a costly and highly embarrassing delay?
In many ways, the project is a microcosm of public projects in 21st-century Ireland: beset by delays, caused by objections on the one hand and unrealistic timelines on the other.
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The first delay was caused by a judicial review lodged by an environmental group, Ballyboden Tidy Towns, that argued for a natural and environmental solution, with flood plains and natural attenuation – storage for storm waters – higher upstream, closer to the source.
The group took its challenge all the way to the Supreme Court, which rejected its appeal in late 2022. This meant it was 2023 before the project began.
On Thursday morning, Minister of State for the OPW Kevin “Boxer” Moran and Minister of State for Immigration Colm Brophy visited residential areas in Rathfarnham where homes were badly damaged by flooding.
Angela Lynam showed them her home and well-maintained back garden; the house floors had been reduced to a muddy mush by the flood, the garden to a mini lake.
Moran promised the defence wall would be finished by June or July. For Lynam and her neighbours, though, this was too late.
On Monday night, when Storm Chandra hit, she heard a bang and came downstairs to see many belongings submerged in water, with her shoes floating in the hallway. It will be months before she can return to the house. She is now staying with her sister in Dunlavin, Co Wicklow.
Brophy, who is a Fine Gael TD for this constituency, said he was frustrated the judicial review case had delayed the scheme.
“If it hadn’t been judicially reviewed and hadn’t been delayed, it would have been completed at this stage. It would not have had the impact on people’s lives and homes that we’re seeing here today,” he said.
“While I accept as a Minister that people have the right to [object], we have to be cognisant of the real impacts on people’s lives.”
[ More flooding expected as rain falls on saturated ground againOpens in new window ]
He referred to another woman who lives close by.
“Her entire home was destroyed. All her possessions and her family keepsakes and mementos have been destroyed by water pouring in. She had to be rescued by the Fire Brigade, taken out of her home on top of a wheelie bin,” he said.
Ballyboden Tidy Towns did not respond to phone and text requests for an interview.
It posted social media comments this week criticising the scheme’s effectiveness as a flood defence, arguing that the “failure to set aside areas upstream for natural attenuation and flood water storage is a huge design flaw”.
For their parts, the council and the OPW have said if the last part of the scheme had been completed, the flooding would not have occurred and the storm waters would have been fully contained.
Some politicians and public figures contacted, including Brophy, said the Ballyboden group involved a relatively small number of people and did not represent the views of the wider community.
However, others privately said that some of its criticisms had some validity and pointed to other reasons for the delay.
The actual works took longer than had been anticipated. Newsletters to local residents from the council listed some of the unexpected obstacles: an “uncharted foul sewer” was found that required protection works, while an uncharted water main was also found.
At another section, it was found that Japanese Knotweed, an invasive species, had spread over a wide area, and its removal took some time. Inland Fisheries rules meant work in stream could only be carried out between July and September.
Local politicians acknowledge there has been considerable delays in the scheme.
“It’ll be three years since they started the work in St Enda’s Park, and it is still not done,” said local Labour TD Ciaran Ahern.
“Obviously, people locally are very frustrated because there’s been huge traffic restrictions on the road for a long time ... You have to assume that had it been completed, it will stop the floods.”
John Laharte, Fianna Fáil TD for Dublin South West, like Ahern, is of the view that, if the scheme was completed, the floods could have been averted. He believes the reason for the flooding is wider and more subtle.
He points to other factors: inadequate culverts, where the stream is diverted underground; blocked drains, and the lack of attenuation in some housing estates between Rathfarnham and the mountains.
“We need to improve more by clearing the drains. And there’s no doubt that construction work seems to have contributed to some of it,” he said.
He added, however, that the scheme for the river Poddle was a success.
“For a stream that’s as wide as a kitchen table, it did some damage when it flooded,” he said.
He says the flood prevention scheme “seems to be working”. In the new housing estates they’ve built in attenuation spaces, so the water is held and stored during storms and then released slowly. That’s very definitely working, it’s holding on to surface water,” he said.
In any instance, the relatively modest scheme is due to be wholly completed by October 2026, six years after it was given the green light.
